title: Mucinous tumor of the appendix with limited peritoneal spread: is there a role for expectant observation?
abstract: BACKGROUND
  Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is now the standard management for mucinous tumors of appendiceal origin at many centers. We examined the role of expectant observation (EO) in patients who had undergone an initial resection at the time of referral to our center and who had limited residual disease.
  
  
  METHODS
  We performed a retrospective review of patients referred to Mount Sinai/Princess Margaret Hospitals, Toronto, for consideration of surgical management of peritoneal malignancy between January 1998 and December 2009. One hundred and three patients with primary mucinous appendiceal malignancy were identified. EO, consisting of regularly scheduled imaging and clinical review, was selected for asymptomatic patients with low-grade tumor and no/limited disease on imaging. Overall survival (OS) and progression-free survival (PFS) were determined.
  
  
  RESULTS
  Management consisted of supportive care in 7 patients, systemic chemotherapy in 7, referral for CRS with HIPEC in 8, CRS without HIPEC at our center in 51, and EO in 30. In the CRS group, 5-year OS was 74 % and PFS was 56 %; both OS and PFS were predicted by extent of residual disease after cytoreduction (p = 0.014 and p = 0.011, respectively). In the EO group, 5-year OS and PFS were 95 and 82 %, respectively. Two patients in the EO group subsequently underwent CRS for progression on imaging.
  
  
  CONCLUSIONS
  In well-selected patients who have undergone initial resection for low-grade mucinous tumor of the appendix with limited peritoneal spread, a formal program of observation can result in excellent 5-year OS and PFS. Longer-term follow-up will help define the benefits and risks of this approach.
authors.affiliation: Department of Surgical Oncology, Mount Sinai and Princess Margaret Hospitals, Toronto, ON, Canada, francis.zih@gmail.com.
authors.forename: Francis S W
authors.initials: FS
authors.lastname: Zih
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wong-Chong
authors.forename: Claire
authors.initials: C
authors.lastname: Hummel
authors.forename: Jennifer
authors.initials: J
authors.lastname: Petronis
authors.forename: Tony
authors.initials: T
authors.lastname: Panzarella
authors.forename: Aaron
authors.initials: A
authors.lastname: Pollett
authors.forename: J Andrea
authors.initials: JA
authors.lastname: McCart
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: McCart
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Swallow
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000401:mortality / Q000556:secondary* / Q000601:surgery / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001063:Appendiceal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D010478:Chemotherapy, Cancer, Regional Perfusion; D003131:Combined Modality Therapy; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006979:Hyperthermia, Induced; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000401:mortality / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D010534:Peritoneal Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D057832:Watchful Waiting; D055815:Young Adult